I've been trying to find this everywhere and I can't remember where I saw it. All I remember is that Dee had an injury and Sam needed to take off her vest and her bra to sow it up. She was wearing a jacket vest of some kind. Sam is maybe 13, or somewhere in his teens and this is all very embarrassing for him because he likes her. She knows it and teases him. I remember there's references to her promiscuity in all the high schools she went to, something about her having sex with all of the guys there and getting bored of them quickly. Sam gets an erection and tries to hide it, I think, and she thinks its cute or something.

I remember it was a rec'd fic. The person said it was the best girl!Dean they ever read because she acts like Dean, having a laid back, masculine, devil-may-care attitude that ringed true of Dean. I don't think there was any sex because Sam was underage.

Thanks!